BOISE, Idaho — For nearly 50 years, Idaho’s prison staffers have been serving Thomas Eugene Creech three meals a day, checking on him during rounds and taking him to medical appointments.

This Wednesday, some of Idaho’s prison staffers will be asked to kill him. Barring any last-minute stay, the 73-year-old, one of the nation’s longest-serving death row inmates, will be executed by lethal injection for killing a fellow prisoner with a battery-filled sock in 1981.

Creech’s killing of David Jensen, a young, disabled man who was serving time for car theft, was his last in a broad path of destruction that saw Creech convicted of five murders in three states. He is also suspected of at least a half-dozen others.

But now, decades later, Creech is mostly known inside the walls of the Idaho Maximum Security Institution as just “Tom,” a generally well-behaved old-timer with a penchant for poetry. His unsuccessful bid for clemency even found support from a former warden at the penitentiary, prison staffers who recounted how he wrote them poems of support or condolence and the judge who sentenced Creech to death.

“Some of our correctional officers have grown up with Tom Creech,” Idaho Department of Correction Director Josh Tewalt said Friday. “Our warden has a long-standing relationship with him. … There’s a familiarity and a rapport that has been built over time.”

Creech’s attorneys have filed a flurry of last-minute appeals in four different courts in recent months trying to halt the execution, which would be Idaho’s first in 12 years. They have argued Idaho’s refusal to say where its execution drug was obtained violates his rights and that he received ineffective assistance of counsel.

A three-judge panel of the 9th U.S. Circuit Court of Appeals on Friday rejected an argument that Creech should not be executed because he was sentenced by a judge rather than a jury.

It’s not clear how many people Creech, an Ohio native, killed before he was imprisoned in Idaho in 1974. At one point he claimed to have killed as many as 50 people, but many of the confessions were made under the influence of now discredited “truth serum” drugs and filled with outlandish tales of occult-driven human sacrifice and contract killings for a powerful motorcycle gang.

Official estimates vary, but authorities tend to focus on 11 deaths. Creech’s attorneys did not immediately return phone calls from The Associated Press.

Jensen’s relatives opposed Creech’s bid for clemency. They described Jensen as a gentle soul and a prankster who loved hunting and spending time outdoors, who was “the peanut butter” to his sister’s jelly. His daughter, who was 4 when he was killed, spoke of how she never got to know him, and how unfair it was that Creech is still around when her father isn’t.